/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.mpp.execution.operator.source;

import com.google.common.util.concurrent.ListenableFuture;
import org.apache.iotdb.db.mpp.common.header.DatasetHeaderFactory;
import org.apache.iotdb.db.mpp.execution.operator.OperatorContext;
import org.apache.iotdb.db.mpp.plan.Coordinator;
import org.apache.iotdb.db.mpp.plan.execution.IQueryExecution;
import org.apache.iotdb.db.mpp.plan.planner.plan.node.PlanNodeId;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.read.common.block.TsBlock;
import org.apache.iotdb.tsfile.read.common.block.TsBlockBuilder;
import org.apache.iotdb.tsfile.read.common.block.column.ColumnBuilder;
import org.apache.iotdb.tsfile.read.common.block.column.TimeColumnBuilder;
import org.apache.iotdb.tsfile.utils.Binary;

import java.util.List;

import static org.apache.iotdb.tsfile.read.common.block.TsBlockBuilderStatus.DEFAULT_MAX_TSBLOCK_SIZE_IN_BYTES;

public class ShowQueriesOperator implements SourceOperator {

    private final OperatorContext operatorContext;

    private final PlanNodeId sourceId;

    private TsBlock tsBlock;
    private boolean hasConsumed;

    private final Coordinator coordinator;

    public ShowQueriesOperator(
            OperatorContext operatorContext, PlanNodeId sourceId, Coordinator coordinator) {
        this.operatorContext = operatorContext;
        this.sourceId = sourceId;
        this.coordinator = coordinator;
    }

    @Override
    public OperatorContext getOperatorContext() {
        return operatorContext;
    }

    @Override
    public TsBlock next() {
        TsBlock res = tsBlock;
        hasConsumed = true;
        tsBlock = null;
        return res;
    }

    @Override
    public boolean hasNext() {
        if (hasConsumed) {
            return false;
        }
        if (tsBlock == null) {
            tsBlock = buildTsBlock();
        }
        return true;
    }

    @Override
    public boolean isFinished() {
        return hasConsumed;
    }

    @Override
    public long calculateMaxPeekMemory() {
        return DEFAULT_MAX_TSBLOCK_SIZE_IN_BYTES;
    }

    @Override
    public long calculateMaxReturnSize() {
        return DEFAULT_MAX_TSBLOCK_SIZE_IN_BYTES;
    }

    @Override
    public long calculateRetainedSizeAfterCallingNext() {
        return 0L;
    }

    @Override
    public PlanNodeId getSourceId() {
        return sourceId;
    }

    @Override
    public ListenableFuture<?> isBlocked() {
        return NOT_BLOCKED;
    }

    @Override
    public void close() throws Exception {
    }

    private TsBlock buildTsBlock() {
        List<TSDataType> outputDataTypes =
                DatasetHeaderFactory.getShowQueriesHeader().getRespDataTypes();
        TsBlockBuilder builder = new TsBlockBuilder(outputDataTypes);
        List<IQueryExecution> queryExecutions = coordinator.getAllQueryExecutions();

        if (!queryExecutions.isEmpty()) {
            TimeColumnBuilder timeColumnBuilder = builder.getTimeColumnBuilder();
            ColumnBuilder[] columnBuilders = builder.getValueColumnBuilders();
            long currTime = System.currentTimeMillis();
            String[] splits = queryExecutions.get(0).getQueryId().split("_");
            int DataNodeId = Integer.parseInt(splits[splits.length - 1]);

            for (IQueryExecution queryExecution : queryExecutions) {
                timeColumnBuilder.writeLong(queryExecution.getStartExecutionTime());
                columnBuilders[0].writeBinary(Binary.valueOf(queryExecution.getQueryId()));
                columnBuilders[1].writeInt(DataNodeId);
                columnBuilders[2].writeFloat(
                        (float) (currTime - queryExecution.getStartExecutionTime()) / 1000);
                columnBuilders[3].writeBinary(
                        Binary.valueOf(queryExecution.getExecuteSQL().orElse("UNKNOWN")));
                builder.declarePosition();
            }
        }
        return builder.build();
    }
}
